Speech-brain phase coupling is enhanced in low contextual semantic predictability conditions
Date
2021Author
Molinaro, Nicola
Lizarazu, Mikel
Baldin, Veronica
Pérez-Navarro, Jose
Lallier, Marie
Ríos-López, Paula
Metadata
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Nicola Molinaro, Mikel Lizarazu, Veronica Baldin, Jose Pérez-Navarro, Marie Lallier, Paula Ríos-López, Speech-brain phase coupling is enhanced in low contextual semantic predictability conditions, Neuropsychologia, Volume 156, 2021, 107830, ISSN 0028-3932, https://doi.org/10.1016/j.neuropsychologia.2021.107830.
Abstract
Semantic prediction and cortical entrainment to the acoustic landmarks of the speech envelope are two fundamental
yet qualitatively different mechanisms that facilitate speech comprehension. However, it is not clear how
and to what extent those mechanisms interact with each other. On the one hand, richer semantic context could
enhance the perceptual representation of a predictable stimulus, thus improving speech entrainment. On the
other hand, pre-activating an upcoming item could inhibit further bottom-up analyses to minimize processing
costs, thus weakening speech entrainment. To test these competing hypotheses, we recorded EEG activity from
27 participants while they listened to a 14-min recording of text reading. The passage contained target words
presented twice: once in a highly constraining and once in a minimally constraining context. First, we measured
event related potentials on target words in the two conditions. In line with previous research, we showed that
semantic predictability modulated the N400 amplitude: words in minimally constraining contexts elicited larger
negative amplitudes than words in highly constraining contexts between 250 and 450 ms. Second, we evaluated
speech entrainment effects by analyzing phase alignment between neural activity and the envelope of target
words. Importantly, we found increased speech entrainment for words in minimally constraining compared to
highly constraining contexts between 400 and 450 ms. Both effects were located in central electrodes and were
significantly correlated. Our results indicate a trade-off between semantic pre-activation and cortical entrainment
to speech and support the cost minimization hypothesis.